I want to create a block in the drawing sheet to show welding numbers for all welds , I need to assign unique number/name at each place, so I need to edit the  block's text content

I want to create a block in the drawing sheet to show welding numbers for all welds ( Pls see below fig. C1,C3) , I need to assign unique number/name at each place, so I need to edit the block's text content C1 as C2,C4,B11,A1...