The Islamic Republic's effort to spread the revolution is considered to have begun in earnest in March 1982, when 380 men from more than 25 Arab and Islamic nations met at the former Tehran Hilton Hotel for a "seminar" on the "ideal Islamic government" and, less academically, the launch of a largescale offensive to cleanse the Islamic world of the satanic Western and Communist influences that were seen to be hindering the Islamic world's progress. The gathering of militants, primarily Shi'a but including some Sunnis, "with various religious and revolutionary credentials," was hosted by the Association of Militant Clerics and the Pasdaran Islamic Revolutionary Guards. The nerve centre of the revolutionary crusade, operational since shortly after the 1979 revolution, was located in downtown Tehran and known to outsiders as the "Taleghani Centre". Here the groundwork for the gathering was prepared: the establishment of Arab cadres, recruited or imported from surrounding countries to spread the revolution, and provision of headquarters for such groups as the Islamic Front for the Liberation of Bahrain, the Iraqi Shi'a movement, and Philippine Moro, Kuwaiti, Saudi, North African and Lebanese militant clerics.
These groups came under the umbrella of the "Council for the Islamic Revolution", which was supervised by Ayatollah Hussein Ali Montazeri, the designated heir of Ayatollah Khomeini. Most of the council's members were clerics, but they also reportedly included advisors from the Syrian and Libyan intelligence agencies. The council apparently received more than $1 billion annually in contributions from the faithful in other countries and in funds allocated by the Iranian government. Its strategy was two-pronged: armed struggle against what were perceived as Western imperialism and its agents; and an internal purifying process to free Islamic territory and Muslim minds of nonIslamic cultural, intellectual and spiritual influences, by providing justice, services, resources to the mustazafin (weak) masses of the Muslim world. These attempts to spread its Islamic revolution strained the country's relations with many of its Arab neighbors, and the extrajudicial execution of Iranian dissidents in Europe unnerved European nations, particularly France and Germany. For example, the Islamic Republic expressed its opinion of Egypt's secular government by naming a street in Tehran after Egyptian President Anwar Sadat's killer, Khalid al-Istanbuli. At this time Iran found itself very isolated, but this was a secondary consideration to the spread of revolutionary ideals across the Persian Gulf and confrontation with the US (or "Great Satan") in the 1979-1981 hostage crisis.

Accusation: state-sponsored terrorism

https://en.wikipedia.org/wiki/Iran_and_state-sponsored_terrorism

Since the Iranian Revolution in 1979, the government of Iran has been accused by several countries of training, financing, and providing weapons and safe havens for non-state militant actors, such as Hezbollah in Lebanon, Hamas in Gaza, and other Palestinian groups (Islamic Jihad (PIJ) and the Popular Front for the Liberation of Palestine-General Command (PFLP-GC)). These groups are designated terrorist groups by a number of countries and international bodies; however, Iran considers such groups to be "national liberation movements" with a right to self-defense in the face of Israeli military occupation.

Islamic Revolutionary Guard Corps (IRGC)

After the fall of the Shah in 1979, the Islamic Republic of Iran established the Islamic Revolutionary Guard Corps (IRGC) to domestically promote the government's social policy. IRGC is accused of spreading its ideology in neighboring regions by training and funding "terrorist organizations". By 1986, IRGC had 350,000 members and had acquired a small naval and air force. By 1996, its ground forces numbered 100,000 and the naval forces numbered 20,000. They are believed to use the Quds Force to train Islamic militants.
In 1995, the Iranian Revolutionary Guard held a conference with worldwide organizations accused of engaging in terrorism including the Japanese Red Army, the Armenian Secret Army, the Kurdistan Workers' Party, the Iraqi Da'wah Party, the Islamic Front for the Liberation of Bahrain and Hezbollah in Beirut for the sole purpose of providing training to these organizations supposedly to help in the destabilization of Gulf States and aid assistance to militants in these countries to replace the existing governments with Iran-like regimes.
The United States State Department states that IRGC provides support for Hamas, Hezbollah and Palestinian Islamic Jihad in Israel. They also say that IRGC has given much support and training to terrorists supporting the Palestinian resistance. They are also accused of aiding the Iraqi insurgency in southern Iraq.
United States designates IRGC as foreign terrorist organization.

IRGC and Muslim Brotherhood

The 2014 summit brought together the foreign military arm of Iran’s Islamic Revolutionary Guard Corps, known as the Quds Force, and the Muslim Brotherhood, a sprawling Islamist political movement with significant influence throughout the region.
The Quds Force represents the world’s most powerful Shia-dominated nation, while the Muslim Brotherhood is a stateless but influential political and religious force in the Sunni Muslim world. The Trump administration designated the Revolutionary Guards a foreign terrorist organization in April, 2019 and the White House has reportedly been lobbying to add the Muslim Brotherhood to the list as well.
The Quds Force represents the world’s most powerful Shia-dominated nation, while the Muslim Brotherhood is a stateless but influential political and religious force in the Sunni Muslim world. The Trump administration designated the Revolutionary Guards a foreign terrorist organization in April, 2019 and the White House has reportedly been lobbying to add the Muslim Brotherhood to the list as well.
An Iranian intelligence cable about the 2014 meeting provides an intriguing glimpse at a secret effort by the Muslim Brotherhood and Iranian officials to maintain contact — and determine whether they could still work together — after Morsi was removed from power.