What it means
に加えて means “in addition to” or “besides.” It adds another item, condition, or factor to something already mentioned, often emphasizing that both contribute to the situation. It normally follows a noun or noun phrase and is common in formal writing, presentations, reports, and careful speech.
Usage note
に加えて normally follows a noun or noun phrase. To attach it to a verb or adjective idea, first nominalize the idea with こと or a similar noun expression. Do not confuse it with に加え, which has the same meaning but is somewhat more concise and formal.
How to use it
Nounに加えて
この計画は費用に加えて、時間も必要です。
This plan requires time in addition to the expenses.
Nounに加えて
この計画は費用に加えて、時間も必要だ。
This plan requires time in addition to the expenses.