Microsoft Word's Replace feature is under-used because the more complex the requirement, the more complex the solution. If you're inserting characters into the middle of a string, there is a solution.

Find and Replace in Word is a tool that searches a document for a specific word or phrase. You can use it to replace a word or phrase with another.

Microsoft Word's Replace feature is quite powerful. Complex updates don't have to be difficult if you use Replace in Microsoft Word.