Previous to 18 I believe all contacts were only associated with an email address. Your iCloud default email address that comes with an Apple ID if you use iCloud and synch contacts were the list that you had manually inputted in your phone.
All of your other contacts were synched with your email addresses
example blah@gmail.com
or blah@yahoo.com or any other email address. You used to go to settings, internet accounts, and then add your email account there.
With iOS 18 you go to settings, apps, mail, and add your account there.
The issues arise when 3rd party email hosts have now added a layer of security by asking your email account to generate a specific third party password for iOS mail. Now this has not worked for many people. When you add for example a Turbify business email to apple iPhone mail, there is not option to synch contacts.
I don’t know if this is Turbify (which is actually yahoo business mail with a different name). Or that iOS 18 has split the places where contacts are brought into the iPhone.
Now when you go to contacts there is a section on iPhone for accounts. Well you can be logged in to your business Turbify email, but no contacts are showing up.
The work around that seems archaic and medieval:
go on the web to your web host login page, login to your respective email account, go to contacts, select all, click export. (If you are on a mac, or have a more advanced web host you can export to VCard). If you are on a PC and your webhosting is not that great either, your only export option is a .csv file that opens in excel, numbers or google sheets.
At least you can get access to your contacts now. You don’t have to manually input them.
Now go to iCloud.com, login to iCloud using your Apple ID and password. Go to contacts, in the far right corner click on the plus sign. If your contacts were exported in vCards, go to the place you saved them on the computer and upload them. You may have to do this one vCard at a time. (At least today I had to do that on a PC for a client but haven’t tried it on a mac yet.) If you only have a .csv file you have to convert that excel spreadsheet .csv file to vCards. There are some free vCard creators and there are paid. I haven’t settled on one that o like yet but you will have to convert the .csv file to vCards and then follow the iCloud instructions above. Now, make sure your iPhone or iPad has /contacts turned on to synch with iCloud so that the iCloud.com (basically your mother ship to all of your other apple devices) will be in iCloud and mirror out to all your apple devices where you have logged in to your Apple ID. I am super upset with difficult third party web hosting, and for apple for splitting something up and not realizing the limitations of email web hosts, and thinking that this upgrade would be ok. I still have to convert try clients .csv files to vCards. What I truly don’t understand is why anyone at apple in the stores or when you call them, why they can’t ask people what email addresses they used to have on their iPhone and then telling them to re-add those accounts. My client had called apple and been to the Apple Store and they said there was nothing they could do. I am losing faith in apple. This seems pretty basic. Hopefully this helps some of you recover your contacts. My client was over the moon that at least I had a spreadsheet for him. This is a small business. I have never listed in these forums but I couldn’t find anything like what I am writing. Good luck and I hope this information is helpful to anyone.