You can use Rules to automatically applied a tag to any transaction that matches a set of filters (like keywords in the description).
Let's say you want all purchases you make at a store named
"Safeway" to be tagged as grocery. You can accomplish this by
creating a tagging rule with the tag grocery and keyword safeway.
Any future transactions which contain the word safeway in their
description will be automatically tagged as grocery.
To create a rule, click Add > Rule.