You may need a visa for Iran if you have a Zimbabwean passport
Visa options for Iran
Electronic visitor visa is required for trips longer than 15 days
Travellers need an electronic visitor visa for Business or Tourism if they stay in Iran for longer than 15 days. Travellers don’t need a visa to visit Iran for Tourism for a maximum stay of 15 days or less. Travellers may enter Iran every six months or two entries per year, with a maximum stay of 15 days for each visit. The 15-day stay is non-extendable; visitors who wish to remain longer must apply for a visa.
This is not offered by sherpa°.
Apply on the government site.