You may add the API to the permission set and grant that permission set to the users you need to grant.

 

Hi @ZTC ZTC JGOTA,

While you can grant access as Ragaventhan shown above, to answer your question regarding a specific function you can grant by expanding its + mark and selecting the needed method. (My example is INVOICE_ITEM_API.Cancel_Prelim_Item):

And you check other grantees/roles by RMB on the required method → click ‘Show Grantees’

It will list down all the permission sets which are using this particular method.

If you want to see the users who have been granted with a particular permission set, search the permission set in ‘New Permission Set’ window. Then in the top right corner click ‘Show Users granted this’ link. It will list down the users.

After performing grants please refresh dictionary and security cache.