Introduction
If you have been assigned an Adobe Creative Cloud license you should have Adobe Sign. With Adobe Sign you can request signatures from one or more people by email. This goes through a process which will notify you once all signatures are collected. You will get an emailed copy of the resulting form, and the resulting signed form will be saved to the SharePoint document library as well. The people you request signatures from do not need a license. They just need the free version of Adobe Acrobat Reader.
Requesting Signatures
Option 1
For this option, you must be working from a document library on a SharePoint site that is authorized for eSignatures. If the site you wish to request signatures from is not authorized, the head of the department that manages the site will need to request ITS authorizes the site.
From a SharePoint document library, open the pdf you would like to request signatures for in the web browser. If the site has been authorized for eSignatures, you will see a pen icon in the upper left menu:

Click on the pen icon. You will be presented with a pop up in order to sign in to Adobe Sign. Click Continue and sign in.

The Adobe Sign webpage will open and you will be guided on requesting signatures. Turn on Complete in Order if you require signatures to be obtained in a specific order. Enter each recipient’s email and name. You can choose Add Me if you want to request yourself to sign the document. Change the message if desired. Select the appropriate options. Add files if needed. Click Next.

This will process and then you will see the pdf with a new menu on the side for signature options.

There are a variety of fields you can add to your document. The ones you are likely to use, however, are in the Signature Fields drop down. For example if you want a signature drag and drop the Signature field to where you want a signature in your document.

Make sure you change the recipient at the top before dragging and dropping a field to your document. Each field will be color coded to the person you are requesting action from. Notice the colored triangle in the top right of each signature request field in the form:

Once you have placed all of the fields you are requesting, click the Sign, then Send button.
You will get an email stating that your document has been sent out for signatures. It will have a copy of the unsigned pdf attached.

Each person will get an email requesting the document be signed.

You will receive updates as people sign the document. There will be an attached document with the updated signatures.

Once all participants have signed the document you will get a final email with the signed document attached.

This signed document will also be saved to the document library the document originated from. It will be saved in a folder named Apps. The full path is Apps > Signed Documents > Adobe. The original document will remain unsigned.

Option 2
From SharePoint, you can also open a PDF you want to request signatures for in the desktop app. This can be done a few different ways.
First, you can click the three dots, go to Open, then select Open in app.

Second, if you have the document library synced to your computer you can just open it from File Explorer.

Third, if you open it in the web browser you can select Edit, then select Open in app.

One you open the pdf in the desktop app, you can request signatures, just like you would for a pdf stored anywhere else. Click on Request e-signatures and follow the prompts.

Alternative way to have a document signed
There is another option for signing a document in SharePoint. This option does not require a license. There may be a time when you don’t need a signature digitally certified or legally binding, and you just want acknowledgement. In this case a document shared in a SharePoint document library can be opened in the desktop app and signed using the signature tools. Multiple people can sign this document, but if the document is opened and signed by two or more people at the same time before it is saved, the last save will be the one that shows in SharePoint, and the other person’s signature will not be saved. It is not possible to do this if you open the pdf in the web browser
When using this method, each person you want a signature needs to follow these steps:
Open the document and click Fill & Sign.

If you already have a signature saved, you can skip the next step. Click on Add signature.

You can choose to type, draw, or use an image for your signature. If you type, you can select the font that best matches your signature.

If you type, you can select the font that best matches your signature. Uncheck Save signature if you do not want to use this signature in the future. Click Apply.

Now you can drag and drop your signature to the document.

Once you are done adding your signatures to the document, you can save it.