We adopted a 4 year old lab mix about a month ago. The shelter told us she was house-trained but she is not. One big problem is that we will take her out for a walk where she won’t go and then she goes to the bathroom in the house almost immediately after we get back.
same as you would a puppy, if she goes in the house, put her in front of the mess and say NO! then bring her outside, if she goes outside, lots of love, good girls and treats, make a big deal out of it! its best if you catch her in the act and take her outside to finish, then, when she does finish outside same as the above, make her feel really good about it! but you have to be consistent! also if she goes at night while your asleep, get her a crate, one where she can turn around and lay down but not enough room where she can go potty and not avoid it, dogs don’t like to go to the bathroom somewhere where they cant avoid laying in it
house training is the same whether you have a puppy or an adult dog. crate train it. feed it once a day, same time. take her out an hour after her meal. stay out with her until she does her business. Crate her at night and when you are gone, or when you are busy doing chores around the house and cannot watch her.