where do i obtain a SIM card for my older iPhone

mmeieio wrote:

So the SIM card comes when you pay for a phone line - already have Verizon phone service on a 6ES.

But a new SIM card is available only if I pay for a separate phone line ?

Well, you need a separate phone line if you want to make calls from the old iPhone. The sim card is what holds the phone number and your carrier settings. Its what enables the phone to make calls and send messages. You cannot magically make phone calls without a phone line. You can always insert a deactivated sim card if you really wanted to, but then you won't be making any calls as it would have no phone service.

The other option is to use the 5c as an extension of the 6s or SE. It would receive calls and messages sent to the number on the 6 while they are both connected to the same Wi-Fi network. See here: Make and receive calls on your Mac, iPad, or iPod touch - Apple Support

I wanted to change the speed of the voice when I select "speak" in a text or email, etc.

But the answers say "go to General, then Accessibility ..." - there seems to be no Accessibility link under General on my 6ES & iPad, but there is on my old iPhone 5c. I did find a separate link in settings > Accessibility - which contains VoiceOver.

If running iOS 10 as a 5c would be, you need to go to Settings->General->Accessibility.

If running iOS 12 or later then the option is directly in Settings->Accessibility. As it was moved.

Also the option to control speech speed in under Spoken Text also found in Accessibility.

See here: Hear iPhone speak the screen, selected text, and typing feedback - Apple Support

mmeieio wrote:

Thanks. Are they costly ?

That depends entirely on your cellular service provider of choice. Generally the sim cards are free from most carriers, what will cost you money is the actual cellular phone service to make calls.

Internet access can be done through Wi-Fi, you don't absolutely need cellular service for that unless you want to access it when away from Wi-Fi.

Contact your cellular provider.

That depends on the cell carrier.