How can I get more service on my iPhone 7

Some cellular services offer roaming for additional fees.

Those may add up significant costs to maintain access.

Sometimes at various levels, your provider may offer a

wider range of coverage. This may or not be viable.

I've limited cell coverage, w/ insignificant data+time.

Those pay as you go ones, use a refillable card; yet

that might not work across your intended travel route.

But you should start with the phone service you have.

Then inquire in detail; and deeply. Faster plans use

more data, cost more, and a trade-off against thrift.

There's few providers in my region; and the giant that

says it's local has no customer service or tech support

in my state; in fact its totally 'out-sourced' everything.

And sells their services wholesale to other brands here.

To even add minutes for data or voice, my calls go to

either Mexico or Philippines.. And it seems insecure.

Newer phones and plans may be acquired from the

larger cellular providers, in your area; they seem to

offer ones with new battery; and limited guarantee.

Helps to always ask, and if you know enough to go

check another carrier or business, figure on that.

Don't settle unless you feel like you've gotten facts.

Advice might be OK from 'consumer report' articles

if you subscribe, as I've done (paper edition is best.)

Contact a cellular carrier in your area and sign up with them.

If you already have a service plan with your carrier but it's not working, you will need to contact them for help with their service.