The root canal procedure itself can be done in one day in most cases.
But you will usually have at least 3 dentist visits before the root canal procedure is done because the dentist will likely do some x rays, give you medicine etc before the root canal is actually done.
However some root canals can be done in just one dentist visit if the tooth infections you have are not too severe.
If the dentist finds more things wrong with your gums or teeth then they may want to wait awhile before doing the actual root canal to make sure everything goes smoothly.
Just like with a tooth extraction the dentist will usually do x rays and then after one or two dentist visits then the tooth will be pulled unless it's an emergency where the tooth needs pulled.