Do not and Don't are two kinds of usage in English grammar that show some difference between them. Don't is the condensed form of the expression 'do not'. Don't is very frequently used in spoken English, whereas 'do not' is used frequently in written English. This is the major difference between the two forms.

Do you use don't or do not?

Don't is the shorter form of 'Do not'. In earlier days, at the time of writing, people used 'Do not' and while speaking, used to say 'Don't'. However, nowadays there is no such distinction and both the forms are used while speaking or writing.

Can I use do not instead of don t?

Don't is a contraction of do not, while doesn't is a contraction of does not, and they both act as auxiliary verbs. In English, don't is used when speaking in the first and second person plural and singular and the third person plural ("I," "you," "we," and "they").