delete remote desktop from mac air

Nothing if it is not used.

what will happen if i delete remote desktop

You get back a pitifully small amount of space, and will be in the same situation tomorrow.

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I would look in the downloads folder for stuff you downloaded once, but do not need any more, including the disk image files and packed images of things already successfully installed or deleted.

If you are serious about this, consider running OmniDisk Sweeper or similar Utility to find the really BIG things. then you can choose whether to keep them or not.

NB> DO NOT use any "Cleaner" Programs on your Mac (or any program that does this "automatically") unless you like spending time re-Installing after they throw away important components of Mac OS X.