I need to validate text fields in magento shipping address popup in checkout page.I can edit validation for other forms locally.I tried many thing still not able to find the solutions.please send the location of file in magento folder and where to change the validation??
You need to create a plugin that will plug on
Magento\Checkout\Block\Checkout\LayoutProcessor::process() method :
public function afterProcess(LayoutProcessor $subject, array $jsLayout): array
// change $jsLayout here
The data you want to change lays under
components/checkout/children/steps/children/shipping-step/children/shippingAddress/children/shipping-address-fieldset path in the
$jsLayout array. Each child of this fieldset is a shipping address form field. Add some validation rules there. You can follow this article for more details.
Note that you can use
Magento\Framework\Stdlib\ArrayManager for easier read/write in a deeply nested array.
Also note that you can create your own validation rules, and add them in the checkout validation rules pool like described in this stackoverflow answer : Add rule to rules.js Magento2 (they also describe how to update the jsLayout data, but I think the example is a little over-complicated, that's why I gave the first link).