The Move Clips button is available on the collection toolbar, except when the Clipboard tab is active. You can also find this button on the AceText Tower.
When you click the Move Clips button, a popup menu appears below it. When you press Ctrl+M on the keyboard, the same menu appears to the right of the list of clips. The menu lists all AceText collections that you have opened, except the active collection. Select one of them from the menu to move all selected clips and folders into that collection.
If the selected clips and folders are inside one or more folders, the same folder structure is created in the collection you are moving the items into. If the folder structure already exists in the target collection, the items are placed into the existing folders.
By default, read-only collections are not listed in the popup menu. They will be if you turn on “try to obtain write access when activating a read-only collection” in the Files Preferences. If you select a read-only collection to move clips into then AceText will try to obtain write access before duplicating the clips. If it can the clips are moved. The target collection is not automatically made read-only again until one of the other options in the Files Preferences kicks in. If AceText cannot obtain write access then it pops up a message saying so.
See Manage and Arrange Text to learn how to use AceText.