IOS update

Firstly, iOS is used on iPhone and iPads and as such will never be found on the macOS Apple Store. In you screen shot & using High Sierra and below - this has become the norma. Apple is not support High Sierra and below and thee is nothing about the Apple Store we can done about it. Only Apple could if they decide to.

Now, if what you really mean an upGrade from High Sierra to a newer version of macOS - see below instructions.

The Age of this computer will Govern what newer version of macOS it will Qualify to install. Use About this Mac from the Apple Icon on Desktop - the required Information will be there.

With the above information in-hand - follow this How to get old versions of macOS and verify what version this computer Qualifies to install. Make sure to use Only Safari to commence the download as Other may not work

Make a Time Machine Backup Before attempting. Notation - Mojave is the Last version to support 32 bit applications / extensions and Drivers. Catalina and Big Sur Only support 64 bit and there is not workaround.

Are there any AntiVirus, Disk Cleaner, Optimizers, Defrag, VPNs etc installed which should be removed as per Developers Instructions. They are useless, unneeded, cause havoc and interfere with the normal operation of the OS and may even Corrupt the OS requiring a Reinstallation.

Again in your previous screen shot - Uncheck the " Set date and time Automatically " and manually change to correct date and time and year.

The little Padlock in lower Left of your screen shot must be Unlocked by click on the padlock and inputting for computer password - then, change the date, year.