A residence permit in Latvia (Uzturēšanās atļauja in Latvian) is a document (ultimately a physical residence card), which provides a foreigner with the right to reside (live, work, study or do business) in the Republic of Latvia for a definite or indefinite period depending upon the type of permit issued.

A residence permit makes your life much easier if you want to spend longer than 90 days in Latvia as well as making your travel to other Schengen countries (members of the Schengen Area) easier, since any person holding a residence permit in one Schengen country does not require any further visas or documentation to visit another Schengen state for the purposes of business or tourism.

Currently there are two main kinds of residence permit issued by the Republic of Latvia: Permanent and Temporary.

At the moment, if you are not personally connected to Latvia or anyone already there in a way which would entitle you to a residence permit (i.e. EU Citizenship, Family reunification, Family immigration, Latvian Ancestry etc.), then there still exists in Latvia two major ways to receive a residence permit:

Residence permit based on the purchase/aquisition of real estate.
If you are willing and able to purchase suitable property or real estate in latvia then you might have the option of a 5 year residence permit based on real estate purchase
The property purchased can be used for any purpose: you can live in it, rent in, sell, or do anything else
Residence permit based on investment.
If you have funds to invest in a new or existing business in Latvia then a residence permit based on business investment might be an option for you.
If you have funds to invest, but prefer more security than can be offered by a business investment, then a residence permit based on financial investment in a Latvian Bank might be the option for you.