I have created a flexible width CTA button with a fully clickable. Previously on the outlook email client, only the text area is shown as clickable. Now using this code you can create a flexible width, fully clickable, and rounded CTA.

<table width="100%" cellspacing="0" cellpadding="0" border="0">
    <tr>
        <td align="center" valign="top" style="padding:20px 15px;">
            <!--[if mso]>
            <v:roundrect xmlns:v="urn:schemas-microsoft-com:vml" xmlns:w="urn:schemas-microsoft-com:office:word" href="https://www.uplers.com/" style="height:52px;v-text-anchor:middle;mso-wrap-style:none;mso-position-horizontal: center;" alt="Flexible CTA Button" arcsize="10%" stroke="f" fillcolor="#0000FF ">
            <w:anchorlock/>
            <center>
            <![endif]-->
            <a href="https://www.uplers.com/" style="background-color:#0000FF;border-radius:5px;color:#FFFFFF;display:inline-block;font-family: 'Open Sans', Arial, sans-serif;font-size:16px;font-weight:bold;line-height: 52px;text-align:center;text-decoration:none;-webkit-text-size-adjust:none;">&nbsp; &nbsp; &nbsp; &nbsp; Flexible CTA Button &nbsp; &nbsp;<img alt="" src="https://image.s7.sfmc-content.com/lib/fe8e1373776d037c71/m/7/370bbff4-1bcd-44ae-8284-739d3519c80f.png" style="display: inline-block;" width="6" height="10" border="0"> &nbsp; &nbsp; &nbsp; &nbsp;</a>
            <!--[if mso]>
            </center>
            </v:roundrect>
            <![endif]-->
        </td>
    </tr>
</table>

Replace content and style as per your needs. Let me know if you facing any issues with the code.