How can i download ios using mobile data?

iPhone 6 can run iOS 12.5.6, but not iOS 13 or later.

• There were size limits for up to 100 MB on iOS 10 or earlier. The idea was to not burn through the data limits of the plan with your mobile provider.
• There were size limits for up to 150 MB on iOS 11.
• There were size limits for up to 200 MB on iOS 12.​ The iOS 12.5.6 update is about 275 MB if updating from iOS 12.5.5. More from earlier versions.
• iOS 13 allows some tweaking for App Store file limits, but not iOS updates.
• iPhone 12 or later with 5G (iOS 14.1 or later) will have an option to “Allow more data on 5G” in Cellular Data Options.

For iOS updates, use Wi-Fi or use a tethered computer with iTunes or modern Mac (without iTunes) through the Finder.

silia195 wrote:

How to download ios update in iphone6 using mobile data not wifi?

iPhone 6 updates are available via computer, via Wi-Fi, and via JetPack or MiFi or similar carrier options.

Update via cellular or hotspot is not an option on iPhone 6.

iPhone 6 cannot be updated to iOS 13 or newer.

You can’t.