The name can be any part of the name. Search looks for %nam% where nam is what you have requested, and the '%' part matches any text before or after your entered value. Names will compare equal regardless of case (upper or lower case), and letters with accents or other marks compare with unmarked letters. Digits and some punctuation marks are not accepted. For example, entering cher may find Cheryl as well as Hatcher.
If you place a percent character (%) in the middle, it will match any set of characters. Try 'j%mac' for example. A blank is treated as a '%' character. After a period, a '%' is inserted for you.
The underscore character '_' matches any single character. This means you can search for J_n and find names Jan, Jen, Jon, Jane, June, Jennifer, Jonathan, etc. Note, however, that an apostrophe is stored as more than one character.