Conga Composer can render Salesforce URL fields as clickable links. The field within Salesforce must contain an absolute (complete) URL address. You can also specify the link text to display in the merged file instead of the URL value.

HYPERLINK
Syntax{{HYPERLINK:FieldName:DisplayText}}
ValuesFieldName is the name of the field from the Template Builder window.

DisplayText is an optional suffix to provide friendly display text rather than the entire URL.

Usage{{HYPERLINK:Company_Website:Visit our home page.}}

After merging, appears as:

Visit our home page.