FORMAL LETTER:

• Yours sincerely: This phrase is commonly used in business/information letters.

• Yours faithfully: Used in formal letters, when the name is not known. You can switch between these two phrases, when writing a formal letter.

• Regards: Very commonly used for business, however, it is less formal.

INFORMAL LETTER:

• Yours truly: Used in personal letters to friends in business.

• Best wishes: Used in personal letters to friends.

• Love/Lots of love: Used in personal letters to family/close friends.

You can also use phrases like yours affectionately, yours lovingly and similar phrases.