Telephone Number Validation (Only Numbers) On Checkout Page Magento 2

To validate telephone number you can use invalidate-number your module checkout_index_index.xmlfile.

<item name="telephone" xsi:type="array">
    <item name="config" xsi:type="array">
    <item name="tooltip" xsi:type="array">
        <item name="description" xsi:type="string" translate="true">For delivery questions</item>
    </item>
    </item>
    <item name="validation" xsi:type="array">
        <item name="min_text_length" xsi:type="number">10</item>
        <item name="max_text_length" xsi:type="number">10</item>
        <item name="validate-number" xsi:type="number">0</item>
    </item>
</item>