Every now and then I receive a telephone number via an SMS. My cell phone recognizes it as a telephone number but quite regularly when I click it, the format cannot be interpreted correctly. Since I cannot edit the wrong number inside the telephone app, I have to remember the number or write it down. In either case, I am forced to manually insert the number in a correct format, which somehow misses the point of the SMS in the first place.
The most sensible solution is to send the phone number inside the SMS in a correct format. The question is what is a correct format?
My favorite format, which has worked for more than a decade, across several cell phones including my recent iPhones and various providers, is:
+country (region) company extension, which for my number would be
+49 (69) 798 42547, i.e. +49 (69) 798 42547
For private numbers I usually do not use the last blank. However, if the local number has seven or more digits I usually insert a blank for readability, i.e. 1234567 would be inserted as 123 4567). All my contacts and all my various email signatures use this format.
What I do not use: 0049 …, +49 (0)69 798 …, +49 (069) …, … 798 x42547, i.e. I avoid the unnecessary and most often misinterpreted zero. In any case, if you do not believe that this is an issue, send few numbers in different formats to your cell phone and check, which work without any hassle.