To add a tag to an account, just select an account, click in the tag panel and type. To delete it from the panel, click the "x" to the left of the tag.

To delete tags from the list of created tags go to Settings->Producers/Tags.

You can use tags in two ways:

COUNT_TAG("tagname") returns the number of appearances of this tag. Use this formula to count the number of crew members from a certain country that generate visa costs for example.

SUM_TAG("tagname") returns the sum of all accounts with this tag. Use this formula to calculate markups on certain elements for example.

Formulas can be used in combination with all mathematical standard operations: +, -, /, *

You can use formulas in the quantity and price/unit fields in Budgeting, as well as the base field in additional charges.