$1 will be the first argument of your bash script:
#!/bin/bash
directory="$1"
echo "$directory"
You can also perform some checks, e.g.
#!/bin/bash
directory="$1"
[ -z "$directory" ] && echo "Please provide a directory" && exit 1
[ ! -d "$directory" ] && echo "Directory not found" && exit 2
for file in "$directory"/wid_*.jil
do
mv -i "${file}" "${file/orig/update}"
done