Add user to Visio licensing group:
Okta Admin >> Directory >> Groups >> Select "APP - M365 - Visio License" >> Assign People >> Search up the requesters name >> Hit the + on the right and hit save
Office Link:
https://portal.office.com/account/?ref=Harmony
From My Account, select View apps & devices. Find Visio from the list and choose the 64-bit or 32-bit version, then select Install Visio