Other than underlines and strikethroughs, how can you represent insertions and deletions in a document?

Answer 1

You could always go SCP style with "Today was a good day. [REDACTED] only did [REDACTED] and left the second [REDACTED] alone."

If it's in dialogue, you could have the character stop just before they actually say the thing and instead say it in their internal monolouge for the readers to see. ->

He bites his lip. "All I wanted to say was..." I love you.

"What?" She bites out at him, tinny through the phone. He can imagine her signature sneer marring her features.

"You disgust me," he finishes, hastily hanging up the phone before he can say something that he regrets. "Well," he says to the empty air of his half-unpacked apartment, "That went well."

Of course, there's a good chance I'm misinterpreting this question, but good luck!