With Lightning Forms, you can create more than one New Form, Edit Form, and Display Form for your lists. Each secondary form can be accessed via its direct link, which opens up to a full window form.
Users who would prefer to open their secondary forms via a side panel can do so in conjunction with Lightning Tools Actions.
After installing Lightning Tools Actions, add the web part, add a button, and configure the Open Form action.
Select the list from the current site, choose the secondary form you want to display, how you want it to open (panel or new window), and if you select panel, specify the width of the panel.
With that done, clicking the "Open 2nd New Form" button on the Lightning Tools Actions web part opens the 2nd New Form in a medium-sized side panel on the same page where the web part was added.