Activate hyperlink on a custom column in document library/list in Default View

You can do it by setting LinkToItem="True" attribute in the default view for list or document library.

You can use SharePoint Designer for this, open your list or library and then your view and make change like shown below:

<ViewFields>
     <FieldRef Name="DocIcon"/>
     <FieldRef Name="LinkFilename"/>
     <FieldRef Name="Modified"/>
     <FieldRef Name="Editor"/>
     <FieldRef Name="FileSizeDisplay"/>
     <FieldRef Name="CustomLink" LinkToItem="TRUE"/>
</ViewFields>


If you want to set any specific URL, then you can create a "calculated column" by using a formula with existing column and use this new calculated column in above example.

=CONCATENATE("http://YourDomain/sites/SiteCollection/Lists/ListName/Forms/<<any form name>>.aspx?ID=",ID)