The doorbell rings once, and your dog is already at the door, barking, before you have moved. It has been this way since they were young.
Why the doorbell sets this off
The doorbell itself is meaningless noise. What matters is what it has always predicted, which is a person arriving, and arrivals are exciting.
You cannot train the excitement about visitors away by ignoring it. You can teach a different, calmer response to the same sound.
Teach a station instead of the door
Pick a mat or a spot a few feet from the door, somewhere your dog can see it but not reach it.
Reward your dog generously for standing or sitting on that spot, with no doorbell involved yet. Build this until it is an easy, familiar habit.
Once the spot is solid, ask for it right before you open the door for a known, calm arrival, like a household member coming in.
Practise the sound with nobody at the door
Working below the level that sets your dog off is what lets this kind of learning stick. That means starting quieter and calmer than the real thing.
Play a recorded doorbell sound at low volume, from your phone, with nobody approaching the door. Reward your dog for going to their station.
Repeat several times a day, at a volume your dog can hear without reacting, before raising it.
Once the recording is easy, ask a household member to ring the real bell and walk away, rather than entering. Reward the station again.
Build up to a full arrival only once the earlier steps are reliably calm.
Relaxation at the door is trained as its own behaviour, in short repeatable sets, the same way any other Skill is built.
Safety note
Excited barking at the door is a training question. Growling, snapping, stiffening or hiding when someone arrives is not, and neither is a dog who has started doing this suddenly. Stop, and speak to your veterinarian or a qualified behaviour professional. Sudden behaviour change warrants a veterinary examination.
Today's version, in one line: play a doorbell sound quietly tonight, and reward your dog for going to their mat.