Typically, the text style is set to Standard = Romans. So type in the command Style, and change Standard to another font. Try Olde English
Go into project settings, than:
P&ID Class Definitions/Engineering Items
Than select under Annotation with the scroll down which annotaion want to edit.
Than click Edit Block.
Than you can select the tag attribute and modify the text properties.
You can create a new annotation style there too. Or remove.
Just one recommendation on adding new text styles. I tried this before directly inside the block and the style did not work. I had to:
1. Manually open projSymbolStyle.dwg from the project
2. Add the new text style to that drawing and save
3. Edit the symbol block inside Project Setup and the new text style will be available (it will also to all symbols in the project)
I was talking about add new annotation style with the Add Annotation button.
Not about adding new text style to the drawing.