The reception bonus options under receiving allow your league to specify different point values for the player catching the pass.
If you want to give more points for a tight end completing a reception, you would do that here. You could also give fewer points to a runningback making a catch.
It's possible that you have a player listed as RB/WR. They will never be able to get both reception bonuses.
First, it will depend on where you started that player in your lineup. If you start a player at RB, they are only eligible for the RB reception bonus.
If you start one of these players at a flex position, the player will be given the reception bonus based on his primary position.
*Note that all of these will stack with a standard reception if any points are given to the standard stat category (ie. PPR/Half-PPR)