Players unlock the ability to create HQ hideouts by earning sufficient Season Points in previous seasons, with higher ranks allowing an HQ hideout to be placed in better-quality regions. There are more specific details that can be read in the post or watched in the video below.

Content retrieved from: https://massivelyop.com/2021/11/11/albion-online-outlines-headquarters-hideouts-and-power-core-mechanics-coming-with-lands-awakened/.