Hello @David Parth
You can implement <iframe> HTML element to embed the sign-up or sign-in process into your web or single-page app. Please be informed that you can only do this using the custom policies.
Follow this link https://learn.microsoft.com/en-us/azure/active-directory-b2c/embedded-login?pivots=b2c-custom-policy to get the steps to complete this.
Let me know if further assistance is required.
Do accept the answer if this helps.