What are the visa & residency requirements in Tanzania?

"In order to visit Tanzania, foreign nationals must obtain a visa prior to arrival. The process of applying for a visa involves submitting an application form, a valid passport, two passport-sized photographs, and a fee. Depending on the purpose of the visit, additional documents may be required. In order to obtain residency in Tanzania, foreign nationals must submit an application form, a valid passport, two passport-sized photographs, a fee, and proof of employment or business activity in Tanzania. The application must also include a letter of recommendation from a Tanzanian citizen or a Tanzanian company. Once the application is approved, the applicant will be issued a residence permit," mentioned another expat when asked about moving to Tanzania.