I was baptized at age 8 in an LDS Stake Center, which had a build in baptismal font (looks like a small swimming pool) with other children of the same age. We were all fully emerged, and if even a finger or piece of clothing was not immersed, the baptism had to be done over again. I remember one girl was baptized several times to get it right. She kept poking her foot out of the water! It was not during a regular church service, and Mormons don’t have godparents.
Since LDS baptisms are not valid for people being received into the Catholic Church, I was baptized in 2008 in a Catholic Cathedral, during Easter Vigil, standing in a baptismal font that was about 8-10" deep and the water poured over my head three times from a smaller font above. (The smaller font is used for infant baptisms.) There were about 9 other adults baptized that same night, and I had a sponsor/godparent.