Evaluate Current User for Flow – 15 – 18 digit User ID

Sometimes, you want to compare record’s owner with current owner in flow to proceed but {!User.Id} returns 15 digit id but record Owner field is returns an 18 digit id. So comparing becomes difficult here. So, you will have to use casesafeId as shown below-

{!CASESAFEID($User.Id)}

Check below snapshot to know why you need to use 18 digit Id-

Note: You may have to create a formula for {!CASESAFEID($User.Id)} and then use it for comparision.