Mysql – Using MySQL Workbench 8 on RHEL7 gui – When I highlight text in the SQL editor it turns black

According to the MySQL Documentation on LOAD DATA INFILE

For security reasons, when reading text files located on the server, the files must either reside in the database directory or be readable by all. Also, to use LOAD DATA INFILE on server files, you must have the FILE privilege. See Section 6.2.1, “Privileges Provided by MySQL”. For non-LOCAL load operations, if the secure_file_priv system variable is set to a nonempty directory name, the file to be loaded must be located in that directory.

As long as you have FILE privilege, you can do this in SQL Editor

SET GLOBAL local_infile = 1;

The maintenance feature is a bit hidden in MySQL Workbench. You can reach it by opening your connection as usual and right clicking on your schema to open the schema inspector:

You will get a new tab in the editor area with many pages for inspection/maintenance. Click on the Maintenance button at the bottom to open this page:

From there it should be clear what to do.