Hi. There is no point to search them, because "work permit" has another meaning in this game.
It is to limit the amount of foreign players in teams.
When You have bought player and have paid him work permit.. and you sell him.. and want to buy him again, you need to buy the work permit again -- (when your foreign player limits is full).
https://www.managerzone.com/?p=forum&sub=topic&sport=soccer&forum_id=10&topic_id=12173529&post_id=43922132#43922132
Currently I have 3 foreign players (have reached to my maximum), when I want to purchase 4th, I have to buy work permit.
Pay attention when you make bids on foreign players, if "work permit" is displayed on bidding window, means you will be charged that amount of money when you win that player with that current bid.
When you currently have zero foreign players, and you are bidding on market...
... Pay attention where you make your bids - If you have made bids on 3 foreign players and bid on 4th, the 4th will be bid as with work permit - even if you did not win those first 3 . So. When You want to bid foreign players, decide the bids carefully.
A Work Permit costs 10 times the Player's current weekly salary.
Info about Work Permit (scroll down to bottom of page):
https://www.managerzone.com/?p=manual_faq&cat_id=1362