The tags appended to you post suggest that you have an iPhone12. All models of iPhone12 are capable of update to iOS 16.5.1 - at time of writing, this being the most recent available version of iOS.
Whether or not you are able to update any iPhone to a newer version of iOS will be dictated by the iPhone model - and the currently installed version of iOS. You can find this information here:
Settings > General > About
Not sure which iPad you have? Identify your iPhone model - Apple Support
Here is a list of the highest version of iOS supported by recent models of iPhone (for simplicity - “generations” are shortened to a number), older devices being restricted in their ability to be updated:
iOS16.5.1
iPhone 14 (all models)
iPhone 13 (all models)
iPhone 12 (all models)
iPhone 11 (all models)
iPhone X, XR, XS
iPhone 8 (all models)
iPhone SE2/SE3
iOS 15.7.7
iPhone 7 (all models)
iPhone 6S (all models)
iPhone SE1
iOS 12.5.7
iPhone 6
iPhone 5S
iOS 10.3.4/3
iPhone 5/5C
If your iPhone is capable of update to a more recent version of iOS than is currently installed, these support pages outline both the available methods by which the update can be performed - and troubleshooting should you experience difficulties:
Update your iPhone, iPad or iPod touch – Apple Support
If you can't update or restore your iPhone, iPad or iPod touch – Apple Support
If your iPhone, iPad or iPod touch won’t update - Apple Support
iOS update and restore errors – Apple Support
Be aware that while an iPhone may be capable of update, in some circumstances you may need to use a computer to perform the update. To do so, you will need access to either a Windows PC (with iTunes for Windows installed) or a Mac (with iTunes or Finder - as appropriate for the installed version of macOS). Ensure that your installed version of iTunes has been updated to the most recent version; the essential device drivers are included.
Download and use iTunes for Windows – Apple Support
Update to the latest version of iTunes – Apple Support
Update software on iPhone, iPad or iPod touch in iTunes on PC - Apple Support
If you have a beta profile installed, ensure this has been removed from your iPhone - as, otherwise, installation of production software updates may be inhibited. This support page provides the necessary information to remove the beta from your iPad:
How to uninstall iOS beta software - Apple Support
You should note that for your iPhone to install an available update, its battery must be charged to at least 50% capacity - and/or be connected to its Power Adapter.
