Office 365 allows us to create document or folder shares with others using Onedrive or TeamSites. You can access these shared items by logging outlook.office365.com with your full email address and password. However, finding the documents location depends on how it was shared.
Shared with me from Onedrive
After you have logged into outlook.office365.com. Click on the Application Grid and select OneDrive.
Documents/Folders people share with you, specifically, are listed in the Shared With Me view in OneDrive for Business. However, documents people "share with everyone" are not listed in this view.
In Office 365, select OneDrive in the header.
Select Shared with Me in the Quick Action bar.
Team Sites: Any 'Team' you have access to should be listed with a link that will get you to the document area.
Follow sites to make them easy to find later
If you're a member of several team sites in your organization, you may want to start following them for easy access. When you follow a team site, it gets listed on your Sites page. When you follow sites, you can quickly navigate to libraries on these sites from OneDrive for Business, as described in the next section.
To start following a site:
Go to the site you want to start following.
Select Follow in the header.
For more information, see Video: Follow a SharePoint site. (link provided by Microsoft)
Go to document libraries in team sites you're following
In OneDrive for Business, you can show a list of team sites you're following in Office 365, and then navigate to document libraries on these sites.
In the Quick Action bar, select Site Folders. You see a list of all sites you're following:
Select a site in the list to see the document libraries on the site.