Govindan Nagappan
Ansys Employee

You can import the excel file into external data and map it to structural model in Mechanical using "Imported load". The excel file can have  X , Y, Z coordinate and the pressure value. 

Example schematic:

Double click on the "set up" cell in external data and select the excel file and specify the details. You should see a preview of your data

Sample preview that shows tempearute import

You can then use Imported load inside Mechanical and apply the pressure on geometry

Check help section: Imported Load (Group) (ansys.com)

External Data (ansys.com)