The .schema command can be used to list the columns in a table. In this example, the columns in the users table in example.db are listed.

~]$ sqlite3 /path/to/example.db
SQLite version 3.34.1 2021-01-20 14:10:07
Enter ".help" for usage hints.

sqlite> .schema users
CREATE TABLE users (
        id INTEGER NOT NULL,
        date_created DATETIME,
        email VARCHAR(100) NOT NULL,
        password VARCHAR(200) NOT NULL,
        PRIMARY KEY (id),
        UNIQUE (id),
        UNIQUE (email)
);

Or like this, as a oneliner command.

~]$ sqlite3 /path/to/example.db ".schema users"
CREATE TABLE users (
        id INTEGER NOT NULL,
        date_created DATETIME,
        email VARCHAR(100) NOT NULL,
        password VARCHAR(200) NOT NULL,
        PRIMARY KEY (id),
        UNIQUE (id),
        UNIQUE (email)
);