Autocomplete? You have entered the given data already?
Where is the data entered?
Magical autocomplete is oft requested and never obtained.
Assuming, as David pointed out, that you're attempting to look up matching data already entered, you'd need to write a script for this. Your script will need to deal effectively with missing data (no match) and duplicate data (It's very easy to have two names that are the same and even duplicate company and phone numbers are not impossible here.)
Here's a tutorial on searching by name. Use the principles from this tutorial for three different scripts (one for each field) and you can do what you want.