The best way to introduce two dogs would be to put them on leashes when they're meeting for the first time. This bounds both of them and lets them know that their owners are close by. Walk them and make sure you avoid any sort of obstacles like fences and gates. Once they start sniffing each other, that's a pretty good sign that they are starting to get accustomed and would welcome the idea of playing with each other.
Letting the dogs meet on a leash is a safe way to introduce the dogs if one of them or both of them have never been around other dogs. The leash gives you more control over the dogs so you can pull them away if they pick up a fight or get rough.
Showing a dog another dog from across the fence will be a great way to introduce them because they’ll see each other from some distance and if they would like to meet, they’ll let you know. Talk to your dog and tell him to look at the dog and ask him if he’ll like to play with the new dog. If the dog shows signs of excitement, happiness, or trust, let them get together and watch how they behave around each other.
This rule applies to your dog and your friend’s or neighbor’s dog. Let them meet for a while and then take them back home. If you want to get another dog and you are not sure how your dog will react to that, you need to check how your dog reacts to other dogs in the room. If your dog likes the other dog, she might play with the other dog or bring her toys for the other dog to play with. Notice their behavior before you make a choice of keeping both of them together or adopt a new dog.
When you are introducing dogs for the first time, leaving them alone right after 10 minutes is not a good idea. Don’t leave the dogs home alone together. Keep an eye on them for a few days and see how they sleep, eat and get along in other activities. Only if they like to share their stuff and genuinely feel happy to have each other, you can let them play or stay alone.
Socialize your puppy