The short answer
It depends on whether you want to keep WordPress. HighLevel sells WordPress hosting, and you can move an existing site onto it with the LC Migrator plugin or by asking HighLevel's team for a White-Glove migration. To leave WordPress for HighLevel's own website builder, there is no page converter: pages are rebuilt and blog posts come over with the blog importer.
Option 1: move the site to HighLevel's WordPress hosting
HighLevel's pricing guide lists WordPress hosting from $10 a month for one site. An agency admin starts the move from the Agency Dashboard under Sites, then WordPress, and picks a method. With the LC Migrator plugin, download the plugin from the dashboard, install it on the site you are moving, select the destination WordPress site in HighLevel and click Start migration, then watch the progress bar on the source site. HighLevel says the plugin has no file-size limits, so it suits large sites. Imported content counts toward your hosting plan's storage.
Sub-account users cannot start a migration on their own; generating the link or submitting the request has to come from an agency admin. If a migration fails, the error shows only in the agency view, and the client keeps seeing it as pending. Once the site is live, HighLevel's setup guide walks through connecting the domain with SSL, turning on security logs, setting user permissions and viewing traffic analytics.
Option 2: a White-Glove migration by HighLevel's team
If you would rather not run it yourself, submit a White-Glove request and a LeadConnector Expert moves the site; HighLevel says most finish within one to three business days, depending on size. You do not share your WordPress password. Instead, install LC Migrator (upload the .zip under Plugins, Add Plugin, Upload Plugin, then activate it), open LC Migrator in the WordPress sidebar and click Generate secure access link. Choose how long it stays active, from 24 hours to 7 days, with 3 days as the default and a 4 day minimum if you create it Friday to Sunday. Paste the link into the request form. You can revoke it at any time.
Option 3: rebuild on HighLevel's website builder
HighLevel's help center does not describe a tool that converts WordPress pages into HighLevel website pages, so plan to rebuild them under Sites from a template or a blank page. Blog posts are the exception. Under Sites, Blogs, open a blog, click New Post and choose Import Blog Posts from URL. The importer scans your blog homepage, asks you to map titles, authors and categories, then imports fully mapped posts as published and the rest as drafts. It relies on the blog's sitemap to find posts, and HighLevel estimates 10 to 20 minutes per 1,000 posts. Keep a list of old post URLs to check against before the domain moves.
More answers in HighLevel questions. For costs, see GoHighLevel pricing or run the cost calculator.