It is very common requirement to remove the default links from the footer. You can’t remove the Search Terms, Privacy and Cookie Policy, Advanced Search, Orders and Returns & Contact Us from Magento Admin. They all are coming from the respective module in the Magento.
Search Terms is added via module Magento_Search.
<referenceBlock name="footer_links">
<block class="Magento\Framework\View\Element\Html\Link\Current" ifconfig="catalog/seo/search_terms" name="search-term-popular-link">
<arguments>
<argument name="label" xsi:type="string" translate="true">Search Terms</argument>
<argument name="path" xsi:type="string">search/term/popular</argument>
</arguments>
</block>
</referenceBlock>Privacy and Cookie Policy is added via module Magento_Cms.
<referenceBlock name="footer_links">
<block class="Magento\Framework\View\Element\Html\Link\Current" name="privacy-policy-link">
<arguments>
<argument name="label" xsi:type="string" translate="true">Privacy and Cookie Policy</argument>
<argument name="path" xsi:type="string">privacy-policy-cookie-restriction-mode</argument>
</arguments>
</block>
</referenceBlock>Advanced Search is added via module Magento_CatalogSearch.
<referenceBlock name="footer_links">
<block class="Magento\Framework\View\Element\Html\Link\Current" name="catalog-search-advanced-link">
<arguments>
<argument name="label" xsi:type="string" translate="true">Advanced Search</argument>
<argument name="path" xsi:type="string">catalogsearch/advanced</argument>
<argument name="attributes" xsi:type="array">
<item name="data-action" xsi:type="string">advanced-search</item>
</argument>
</arguments>
</block>
</referenceBlock>Orders and Returns is added via module Magento_Sales.
<referenceBlock name="footer_links">
<block class="Magento\Sales\Block\Guest\Link" name="sales-guest-form-link">
<arguments>
<argument name="label" xsi:type="string" translate="true">Orders and Returns</argument>
<argument name="path" xsi:type="string">sales/guest/form</argument>
</arguments>
</block>
</referenceBlock>Contact Us is added via module Magento_Contact.
<referenceBlock name="footer_links">
<block class="Magento\Framework\View\Element\Html\Link\Current" ifconfig="contact/contact/enabled" name="contact-us-link">
<arguments>
<argument name="label" xsi:type="string" translate="true">Contact Us</argument>
<argument name="path" xsi:type="string">contact</argument>
</arguments>
</block>
</referenceBlock>If you want to remove all the links update your default.xml.
<referenceBlock name="footer_links" remove="true"/>If you want to remove the particular link then update your default.xml with this.
<referenceBlock name="search-term-popular-link" remove="true"/>
<referenceBlock name="privacy-policy-link" remove="true"/>
<referenceBlock name="catalog-search-advanced-link" remove="true"/>
<referenceBlock name="sales-guest-form-link" remove="true"/>
<referenceBlock name="contact-us-link" remove="true"/>Hope this is helpful. Please share your comment or feedback below. Cheers!