If you want to import PST to IMAP  server, the easiest approach is to first convert the PST emails into a format that the IMAP account can handle, then upload them to the required folders. For a large PST or multiple folders, a tool like Advik PST File Converter can simplify the process by transferring emails while keeping the folder structure and attachments intact.

You can import a PST file to an IMAP server easily by using either a manual email client method or a dedicated PST migration tool.

1. Manual Method Using an Email Client
Configure your IMAP account in a compatible email client and import the PST data through a supported process. Then copy the required emails and folders into the IMAP mailbox. This approach may work for smaller mailboxes, but handling large archives can take more time.

2. Direct Migration Using Dedicated Software
If you need to transfer PST emails in bulk, WholeClear PST to IMAP Converter is worth considering. It lets you scan and preview PST files, connect to an IMAP account using server credentials, and migrate emails with attachments. It also supports batch processing and allows you to select an existing destination folder or create a new one without installing Outlook.

Before starting, verify your IMAP settings and check the destination mailbox after migration to confirm that the required emails and attachments are present.