The most commonly seen formatting of a business letter is the block format. This is when all the text is aligned to the left, including the contact information and signature.
The other type of letter formatting you might see around is the indented format, where the contact information and signature are right-aligned while the rest of the text is aligned to the left. The indented format isn’t as common as the block format but it’s an option if it looks good with the letter template you use.