The Header Adjuster plugin streamlines the process of modifying header levels in Markdown documents within Obsidian. It allows users to easily increase or decrease header levels globally or within specific line ranges. With features like modal inputs for customization, default settings for quick adjustments, and a ribbon icon for convenient access, the plugin enhances document formatting efficiency. Users can specify adjustment levels, starting and ending lines, or apply predefined settings for common tasks. Commands for header adjustments are accessible from the command palette, making the plugin user-friendly and versatile.