Adding Breadcrumbs to Magento My account Page.

for adding breadcrumbs to each page , each page needs an action for the link.

here is an example adding breadcrumbs to customer account pages sign in and sign up pages.

For that we have to add the code into customer_account_create.xml inside Magento_Customer module

<referenceBlock name="breadcrumbs">
    <action method="addCrumb">
        <argument name="crumbName" xsi:type="string">account</argument>
        <argument name="crumbInfo" xsi:type="array">
            <item name="title" xsi:type="string" translate="true">Account</item>
            <item name="label" xsi:type="string" translate="true">Account</item>
            <item name="link" xsi:type="string">/customer/account</item>
        </argument>
    </action> 
    <action method="addCrumb">
        <argument name="crumbName" xsi:type="string">account.create</argument>
        <argument name="crumbInfo" xsi:type="array">
            <item name="title" xsi:type="string" translate="true">New Customer</item>
            <item name="label" xsi:type="string" translate="true">New Customer</item>
            <item name="last" xsi:type="boolean">true</item>
        </argument>
    </action>
</referenceBlock>

it can also added using an external module : https://github.com/karliuka/m2.Breadcrumbs

Refer this link for more detail.