convert to pdf/a

On the Combine Files toolbar, click Add Custom Page

Insert from file option in the Organize Pages tool Select the PDF you want to insert and click OpenIn the Insert Pages dialog box, specify where to insert the document (before or after the first or last page, or a designated page)

Click OKTo leave the original PDF intact as a separate file, choose Save As, and type a new name for the merged PDFNote: You can also add an existing file to an opened PDF

Drag the file icon directly into the Page Thumbnails panel in the navigation paneAdd a custom page to a PDF You can add a custom page to your PDF using the integrated Adobe Express app, which offers thousands of templates to choose from while combining files in Acrobat

Steps: Open the PDF in Acrobat and click Combine Files in the right pane

On the Combine Files toolbar, click Add Custom PageAs needed, do any of the following in the list of files: To change the order in which Bates numbers are assigned, select a file, then drag it or click Move Up or Move Down

To sort the list, click a column nameClick again to sort in reverse order

To specify a target folder for output files and filename preferences, click Output OptionsSpecify the options as needed, and then click OK