How can I tell if everything on my phone is backed up before I install a new sim card

Check the last backup date in iCloud, or manually run a local backup to a Mac or Windows computer.

I’ve never seen nor even heard of a report of issues with a SIM swap.

Locate backups of your iPhone, iPad, and iPod touch - Apple Support

How to back up your iPhone, iPad, and iPod touch with iCloud - Apple Support

What does iCloud back up? - Apple Support

Manage your iCloud storage - Apple Support (also shows how to find and check backups)

Dairyproducts2020 wrote:

If I change my phone service to another company which I have is there a way I can get my own personal hotspot or Wi-Fi

Your iPhone must be not be carrier locked by your current carrier, and your new carrier must offer the hotspot feature, or offer MiFi or Wi-Fi device.

Here is ➡️ How to unlock your iPhone for use with a different carrier - Apple Support

Dairyproducts2020 wrote:

OK how on my phone do I get to iCloud

Through a cellular or Wi-Fi or MiFi connection, usually.

You will be able to back up to iCloud over Wi-Fi, or 5G cellular if your iPhone and your carrier both support 5G.

iCloud backups are not available on 4G and earlier cellular connections.

Details on ➡️ How to back up your iPhone, iPad, and iPod touch with iCloud - Apple Support

The blue-colored text here is a link to more information.

Tap on those blue-colored links (from my previous reply here), and learn more about how to do what you want.

I’ve linked to how to check iCloud.

It seems clear you’re not using a Mac or Windows system for backups now, so you’ll have no existing backups there.

Iphones don't store anything on the SIM card.

What is it you think you are going to lose by removing the SIM card?