Fetching details from the dictionary...

to add (one thing to another); to add (a few more words, an explanation, etc.)
報告書に補足説明を付け加える必要があると思う。
I think we need to add supplementary explanations to the report.
彼女は話の最後に重要な情報を付け加えてきた。
She added important information at the end of her talk.
何か付け加えることがあれば遠慮なく言ってください。
Please feel free to say anything if you have something to add.