Hello Michael,
In general, when you want to know where specific text exists, go to your admin, Langauge module, click
the tab "Search" and then search for the text you want or the langauge variable as you see it in the template.
For this specific question, you will find it in the langauge file "AccountMgr" the variable :
check_money_order_payment_help
In this language file you will find all text in the accounts area.
Thank you
Mewsoft Support www.mewsoft.com