In Pleo, click on "Settings", "Accounting", and "Tags".
Click on "Create a tag group". You can create up to 3 tag groups.
Click on a tag group to add an unlimited number of individual tags. To create individual tags, type a single word per line. If a tag group contains a very long list of individual tags, you can also import them from a spreadsheet by clicking on Import.
Good to know:
Holded only accepts one-word labels in lower case.
When you add a new tag in Pleo, it will be automatically created in Holded after an expense with said tag is exported.
When adding info to a specific expense, people are limited to a maximum of three tags (with a 1 tag limit per group).