An array in bash can only be one dimension.

#!/bin/bash
 
create_array() {
    # read a file into an array
 
    local arr=()
 
    while read -r line; do
        arr+=($line)
    done < "/path/file.ext"
 
    echo "${arr[@]}"
}
 
for i in $(create_array); do
    echo $i
done

#!/bin/bash
 
name="$(pwd)/my_file.txt"
 
text=("a aa" 
    "b bb" 
    "c cc")
 
printf "%s\n" "${text[@]}" > $name  # rewrite file if exists
cat $name