You are using Question2answer (Q2A) QA base application. Under the Q2A application answer characters are already set to 12000. You can increase the length of answer characters through the maximum.php file from the DB folder.
I understand your concern. Yes, you can increase the length of characters.
Question2answer allows you to customize the QA application.
Increase maximum content length is 12000 characters in the Q2A application
Navigate to the path -
Edit the maxima.php file and find below code -
QA_DB_MAX_CONTENT_LENGTH' => 12000,
'QA_DB_MAX_CONTENT_LENGTH' => 18000,
Now save your Q2A file and execute. You will not get the error "Maximum length is 12000 characters"
Hope! it will helpful for you.