In WordStar you need to block mark an area of bold text by typing ^PB at either end of the text. This could have been done, but would have added unnecessary complications and screen updates. The WordStar Command Emulator works in a subtly different way, as follows:
To make a single word blod, place the cursor within the word and type ^PB. You can also use F8 to mark the start of a larger area, navigate to the end, and type ^PB to make the whole block bold. This is a cross between WordStar and Word methods of working. If you change your mind, press ESC to unmark the block.
To toggle bold face on/off as you type, type ^PB then the text you want in bold, then ^PB to continue in normal weight text.
The same applies to ^PY (italic), and ^PS (underscore).