Does the fridge have one already or is this a feature you want to add? If already in the fridge and you want to replace, just Google the name and model of the fridge and add 'water filter'. You should get several hits.
If it does not already have one, you might have a project too complicated and expensive to consider. Bottled water sounds easier and less trouble
horsedoc
2008 Damon Essence
2013 Jeep Sahara Unlimited
Blue Ox tow