Calling Card can only use on animals when they are not nearby you. When are at certain level, you will unlock animals friends, but once you unlock they are still new to you.
If you want to meet them and start raise friendship with them you can use a Calling Card to call them to your area for 3 hours. But you only use once (purpose is to complete your stretch goals)
Click on the Animals that you want to call.
Once you call them, they will be around you!
Now it’s time to raise your friendship with them! Now you can check through their list of furniture to craft and so you can invite them to your campsite.
There are lots of happy ending after you completed their request, like enjoying favourite fruits together, making shell necklace, making pudding cake! And many more!