New puppy just 12 weeks old english bulldog female just started today after her nap she was sound like she had flem it was clear it did not last long. Then she was fine played, eat well, drank her water. About 8 pm she started again it could be congestion to I don't know. My vet is closed till Monday

Bulldogs are known for having respiratory problems, however I wouldn't panic. If she is eating and playing fine then she would be OK to wait until Monday to go to the vet.

Was she playing or running around before she coughed or was she just sitting still?
Exercise can cause a few problems with this breed so it's best not to let them get too excited.
Walks should be taken nice and slow and during a cool part of the day (early morning or late afternoon)

There are some other reasons for coughing but the diagnosis is best left up to your vet.

A coughing dog with Flem could be a lot of different things... the start of kennel cough which is just a doggie cold. If she's not real bad and its just an incident here and there then I wouldn't be alarmed... just keep a watch on her and moniter her food and water intake and make sure she has bright eyes... when my pit had real bad kennel cough I gave her musinex. . The green bottle... it helped her nose clear up real fast and she was spitting up mucus.

For sure talk to a vet... they will be able to tell you a for sure answer.