It is not possible to bulk update Client personal information on bulk but you can bulk update the following information. 

• Client Partner - Select from staff dropdown
• Client Manager - Select from staff dropdown
• MTD Qualifying Year - Select 2026/27, 2027/28, or 2028/29 
  • This field only appears if you've selected at least one UK Self-Assessment client

For more guidance on this please go to this Article - Bulk Client Edit