Instagram is a simple tool to share your pictures. No need to have a big knowledge, just add a pic, write something about it if you want to, some hashtags and you’re good to go. You can add the location if it is relevant or tag someone so that he gets notified of your picture. Why not trying the filters too, if you prefer to have your picture in b&w for example.
You may have a business account too. Where you’ll be sharing your products or quotes or whatever is linked to your business. You can use ads to promote your posts if needed. It is so simple to use but only in a phone or tablet, computers are not suitable to upload a picture
For Snapchat silly and funny things attract teens. It is an opportunity to have a profile if your company is related to this age group. Snapchat is an entertaining platform, it is not suitable to sell anything, it is like Instagram and it uses filters too.