Dear Sir or Madam,
Greetings from Top China Travel!
For foreign tourists, they should apply the Tibet Travel Permit from Tibet Tourism Bureau first then can enter the very place. You can first contact with a travel agency locates in China about your Tibet tour plan, when you make a deal, your local agency can assist your clients to make the application – 2weeks before your entry date. More information you can check
Tibet Travel Permits.
Please kindly note that during Jun 25 to Jul 25, Tibet is closed for foreign tourists. If your clients wanna go for a visit, I think you can suggest them make the tour afterwards if possible.
Kind regards,
Zoe