Hi,
As Andy stated, you can enable the Exchange Online Archive for the user with E1 license.
a. Can we increase the storage size in E1 license? No, size cannot be increased and its based on the license
b. Do we have online archive option in E1 license? Yes, exchange online archiving is included in E1
c. If we have online archive option. how do we see those emails in outlook web. Yes, it will display as "In-place archive"
d. How do we archive archive from outlook web. Move the items to the archive folder
e. Is online archive is free? Its included in E1 license
https://www.slipstick.com/office-365/enable-office-365-exchange-online-archive/
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