To Add MRP Column/custom field on mobile, Please follow the below mentioned steps:
Step 1: Kindly go to More option
Step 2: Click on Custom column
Step 3: Click on Add new column
Step 4: Enter the Column name, Select type, Applicable for and Save
Step 5: Once the field is added, it will remain Inactive, Now tap that field.
Step 6: Enable the options you want and Save