The water filter on a Whirlpool refrigerator and many other brands of refrigerators is located on the bottom edge of the refrigerator. To remove the water filter, twist the cap counter-clockwise. There will be a little water that comes out, but there will not be a lot of water. When you twist the filter it will push out a little and you can then pull the water filter straight out. Twist the water filter counter-clockwise to remove it, it may be a little stubborn.
When you have the old filter out, the installation cap will slide off of the filter. Compare it to the new filter and make sure that the fittings and seals match from the old filter to the new water filter.
When you have the filter out, compare the new filter with the filter you removed. Look for any differences in the filter that would inhibit it’s ability to install it.
If the filters are functionally identical, place the cap on the new filter, gently slide it into the hole, gently push it in and twist it until you feel the water filter mounting lugs catch and then turn it clockwise to secure the water filter. Only twist the filter until it is snug, do not force it. When you are using an after-market water filter it may not line up as the original, this is ok.
The refrigerator in this how to article is a Whirlpool model GR2FHTXVQ00 and uses the 2301705 or 4396701 water filter. When replacing the water filter you can use a factory original or an aftermarket version. There will be a significant price difference between a factory original water filter: http://amzn.to/2qZql2Q and an aftermarket filter water filter: http://amzn.to/2qRtaUb . If you decide to use an aftermarket replacement, tin would be wise to note the replacement date and note when you notice a change in the taste of the water.