Please help me on how to update IOS software

I suggest starting with this support article: Update iOS software on iPhone - Apple Support

If you still have issues upgrading or need additional assistance with this matter, you will need to provide more information on what issues you are experiencing trying to upgrade.

Assuming a compatible device, see: Update your iPhone, iPad, or iPod touch - Apple Support

If the above Apple article doesn’t help, please post back with relevant information.