The Select block is a fundamental component that enables users to input information through a
<select> element. Additionally, the Select block offers variations for both single and multiple choice options.
To add a Select block, create a new form and open the Block Inserter tool. Use the search bar to find the Select block and click on its icon to insert it into the editor.
You can also choose the Select block from the “Block Inserter” (+) pop-up window when you click on the (+) sign.
In order to take full advantage of the Block Editor in WordPress, the Select block supports Color settings to modify the text and background colors, the Dimension settings to adjust padding and margin size, and the Border settings to control the width and radius of each side of the element.
Official documentation for these settings controls are available on WordPress.org: