Please find the below XML code to inherit sign_name_and_signature and make sure to declare the xml file in assets -> web.assets_qweb

<?xml version="1.0" encoding="UTF-8"?>
<templates id="template" xml:space="preserve">

<t t-extend="web.sign_name_and_signature">
<t t-jquery="[t-attf-class*=o_web_sign_draw_button]" t-operation="attributes">
<attribute name="t-att-style">'display: none;'</attribute>
</t>
<t t-jquery="[t-attf-class*=o_web_sign_auto_button]" t-operation="attributes">
<attribute name="t-att-style">'display: none;'</attribute>
</t>
</t>

</templates>