Have you noticed that your child recently thinks everything is theirs and will often say “mine” or something similar such as “me” or “my”. It’s definitely early for learning a variety of pronouns, but you can begin with the difference between “mine” and “yours” to make your child aware that items also belong to other people. It the beginning of sharing and empathy!
To start you can show them things that are certainly theirs such as their straw cup, bib, blanket, stuffed animal, etc. and encourage their production of “mine”. Talk about how that is “your blankie”. Then present them with items that they associate with you such as your phone, jacket, shoes, etc. and say “mine”.
You can then talk to them about “yours” by using the same objects for both of you. For instance, if you are both holding ice cream cones you can say “mine” and then “yours” by pointing at the ice cream cones. The more they understand this concept the less likely they will be upset if they do not get to use your computer or phone when you are working from home or just writing a simple email!