How to make an individual holding animation for a tool?

I would like to create an individual holding animation for one of my swords. By that I mean that I would like the character to lay his sword on his shoulder. I know how to create animations. However, I do not know how I can play this animation permanently. In addition, the animation should also be played when the character is running. I would be very happy about links tutorials or any other kind of help on this topic!