create a file using a here-document command inside bash script

How can I create a file using the cat command with a here-document inside shell script"

#!/bin/bash

create_file () {
    cat > a.txt << EOF
    0 abc def 
    ghi jkl mno
    pqrs tuv wxyz
    EOF
}

create_file

Error

Syntax error: end of file unexpected (expecting "}")

remove indentation after opening EOF:

#!/bin/bash

create_file () {
    cat > a.txt <<EOF
0 abc def 
ghi jkl mno
pqrs tuv wxyz
EOF
}

create_file

Bash looks for the same "delimiter" that you started with. You started with "EOF", but was ending with "____EOF" when using indentation, so it couldn't match closing delimiter

if you want add spacing for the resulting text, add indentation to the text, but keep EOF at the start of the line:

#!/bin/bash

create_file () {
    cat > a.txt <<EOF
  0 abc def 
  ghi jkl mno
  pqrs tuv wxyz
EOF
}

create_file