Which add on to use my phone in the United States?

[quiltingpat]

I currently pay £13pm for the 30 Day Essential SIM 25GB £30
Which add on do I need to be able to use my phone in the United States (just text and internet really. I won't need to call anyone)
On my online account I can see the option to add an International Pass, but that looks like it is only for calling abroad from the UK

[Chris_B]

@quiltingpat  You need to read THIS 

[quiltingpat]

Thanks. That was the info I needed. 
I'm asking on behalf of my mum. She is flying to see me this week in America for Christmas, and I was hoping she'd be able to text me when she lands so I know she made it safely and then text again when she is through customs.
Unfortunately at 77, I don't think she will be able to figure out how to activate a data roaming pass if she gets a text when she lands, so I'm hoping she can still text without it

[bristolian]

Whatever billing option your Mum chooses, make sure she enables the free roaming facility on her phone - this is crucial to unlock access to foreign networks and thus coverage outside the UK.

Text ROAMING to 150 before leaving the UK.

[XRaySpeX]

As you are on contract, you may use your usual UK allowances outside the EU with up to 50 GB data per billing month if you have more, when you buy the Zone 1 Pass for £5 / day or £25 / week or already have it as an Inclusive Extra or you have an EE Full Works or EE Max Plan. Otherwise you will need to pay the charges or buy roaming add-ons as set out in https://ee.co.uk/help/mobile/roaming/roaming-costs/countries/usa.

Just remember to text ROAMING to 150 before you leave UK to ensure the roaming ability is enabled on your account.

[XRaySpeX]

If she just needs to send a coupla texts she need do nowt special other than texting ROAMING to 150 before she leaves UK.