R:R stands for Risk to Reward. This figure displays what your anticipated Reward value would be, should the price reached the nominated Target.
The R:R value indicates that for every $x you risk, should the trade reach the target, you will receive $y in return.
Example: If your Projected R:R states a figure of 3.2, this indicates that for every $1 you risk, assuming the trade reaches your target, you will receive $3.20 upon closure of the trade.