There are several methods: Using the "—tag TAGNAME" command-line option, you may tag a new modification that is being checked in using the commit command. To assign multiple tags to a check-in, use the —tag option several times. Tags don't have to be special. Thus, it is typical to tag every released version with the word "release." The tag command can be used to add a tag to an existing check-in. For instance: add a fossil tag CHECK-IN BY TAGNAME Any legal check-in name format may be used for the CHECK-IN in the preceding line.