"Let me + verb" is used to request permission to do something or to offer assistance to someone. The phrase "let me" implies that the speaker is asking for approval to take a particular action or offering to do something for the listener.

For example:
i) "Let me help you with your bags." (Here, the speaker is offering assistance to the listener.)
ii) "Let me know if you need any help." (In this example, the speaker is offering their help and asking for permission to assist the listener if needed.)