To work with your OneDrive for Business files directly in File Explorer and access them even when you're offline, sync the files to your computer. Whenever you're online, any changes that you or others made will sync.
To sync OneDrive for Business to your computer, you need the OneDrive for Business Next Generation Sync Client or the previous OneDrive for Business sync client. This article describes how to sync files using the previous OneDrive for Business sync client, but if the new OneDrive for Business sync client is available in your organization, you should use it. To find out which version of the sync client you have, see Which OneDrive sync client am I using? For info about using the new OneDrive for Business sync client, see the Getting started article for Windows or the Getting started article for Mac OS X.
NOTES
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To sync SharePoint site libraries or on-premises instances of OneDrive for Business, you need to use the previous OneDrive for Business sync client. For info about syncing site libraries, see Sync site libraries to your computer.
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If you recently upgraded from Office 2013 to Office 2016 and OneDrive for Business isn't working properly, see OneDrive for Business is uninstalled after you upgrade to Office 2016 or OneDrive for Business stops syncing libraries after you install Office 2016.
To sync OneDrive for Business to your computer
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Sign in to Office 365 or your organization's SharePoint site with your work or school account.
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Select OneDrive at the top of the page. Or, select the app launcher
, and then select OneDrive.
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Select the Sync button.
NOTE If you don’t see a Sync button, select the Library tab and then select Sync in the Connect & Exportgroup. (You may need to click Settings
> Show Ribbon to show the Library tab.) 
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At the prompt, click Sync Now to start the sync app wizard. The wizard automatically fills in the name and web address of your OneDrive.
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Select Sync Now in the wizard to start syncing.
You can click Show my files… in the wizard to open your OneDrive folder in File Explorer. The folder is listed in your Favorites as either OneDrive - CompanyName or as OneDrive @ CompanyName.
You might see this in File Explorer...
Or this...
When you're opening or saving an Office document, your screen looks similar to this:
