how do i delete iPhoto app on macbook (so I can reinstall and do the updates)?

Then just launch the Photos app. It will offer to import your iPhoto Library, which will remain unaltered. You will lose nothing.

iPhoto has not been updated in many years, and will receive no more updates, so you might as well get rid of it.

Which macOS version is installed on that Mac?

Find out which macOS your Mac is using - Apple Support

Deleting the iPhoto app is probably not a good idea though. It has been replaced by the newer Photos app, which will offer to import the old iPhoto Library.

If your Mac is too old to use the newer Photos app, and you delete the iPhoto app, then you might not be able to access your photos any more. So don't delete it quite yet. First determine if your Mac can be updated so that it can run the newer Photos app instead.