If you want your data from standard input (stdin) to be both written to standard output (stdout) and a file, use tee.
In the example below, ls -l output is written into stdout and output.text file.
ls -l | tee output.txt
total 780
-rw-r--r-- 1 user1 user1 1071 May 11 2024 LICENSE
-rw-r--r-- 1 user1 user1 12213 May 11 2024 README.md
cat output.txt
total 780
-rw-r--r-- 1 user1 user1 1071 May 11 2024 LICENSE
-rw-r--r-- 1 user1 user1 12213 May 11 2024 README.md