There are four kinds of data that need to be migrated manually:
Admin user accounts
Access Control Lists (ACLs)
This section discusses how to manually migrate media files.
The database media storage method is deprecated as of Magento 2.4.3.
This section applies to you only if you store media files in the Magento database. This step should be performed before migration of data:
Log in to the Magento 1 Admin Panel as an administrator.
Click System > Configuration > ADVANCED > System.
In the right pane, scroll to Storage Configuration for Media.
From the Select Media Database list, click the name of your media storage database.
Then, repeat the same steps in your Magento 2 Admin panel.
All media files (images for products, categories, the WYSIWYG editor, and so on) should be copied manually from
<your Magento 1 install dir>/media to
<your Magento 2 install dir>/pub/media.
However, do not copy the
.htaccess files located in the Magento 1
media folder. Magento 2 has its own
.htaccess that should be preserved.
Design in files (CSS, JS, templates, XML layouts) changed its location and format
Layout Updates stored in database. Placed through Magento 1 Admin in CMS Pages, CMS Widgets, Category Pages and Product Pages
You must manually re-create all:
credentials for web service APIs (SOAP, XML-RPC, and REST)
administrative user accounts and associate them with access privileges
You may adjust the time zone for a database entity using the
\Migration\Handler\Timezone handler. See the follow-up section for more details.