Use the wildcard "*"
this will list all the files whose name begins with k followed by any other string of characters. In some cases you can also use the wildcard for a single character "?", e.g. suppose you have files testfile_1.txt, testfile_2.txt testfile_10.txt testfile_11.txt, the command
lists only testfile_1.txt and testfile_2.txt, whereas
will list them all.