The first thing you should know is at what level the document is being requested. You can see this in the list of documents in the "Requested By" column. In this case, it would be a document requested at the "Contractor" level, but it could also be requested at the "Work Center" level.

Next, you must go, in the menu on the left, to the "Contractors" or "Work Centers/Works" section, depending on what level the document is being requested at, and then click on the "Informative documentation" button in the contractor or corresponding center.

If you do not have this section available, you will have to go to the "Miscellaneous" and "Informative documentation" sections:

Once you access the corresponding section, under "Informative documentation" you will see the document that the client is requesting from you and you will only have to download it:

By accepting the reading and clicking on "Download", the document will be downloaded so you can read it:

Now you can return to the list of required documents and you will see that the document has automatically been put in OK status (green).