Follow up, Follow-up, Followup: Which One is Right? - Grammarly
https://www.grammarly.com/blog/follow-up-followup/
WebUpdated on December 23, 2020 Grammar. If you are using follow up as a verb, there is a space between the two words. If you are using it as a noun or adjective, put …
DA: 11 PA: 95 MOZ Rank: 76