Hope you are doing well and sorry for the trouble. As described you want to sign multiple PDF in a batch.
When you apply one or more routine sets of commands to your files, you can save time and keystrokes by using an action—a defined series of commands with specific settings and in a specific order that you apply in a single step. You can apply an action to a single document, to several documents, or to an entire collection of documents. You can even scan documents and combine several documents into a single PDF before running an action.
Acrobat provides some predefined actions. You can also create your own actions. You can access and manage the actions by clicking Tools > Action Wizard.