In Hertfordshire, when I had my first jab (Pfizer) which was arranged through work at the local hospital I was given a card and the date and time for my second jab. However, my husband and daughter who has the AZ jab through the doctor's surgery, got given a card and then had to wait for a text from the doctors to say they could book their second jab.
My eldest daughter in Wales had her first jab through work (Pfizer), was given a second date but this subsequently got brought forward.