How can i submit my form data in custom table magento2

Create a controller in your Vendor/Modlue/Controller/Index

    <?php

namespace Vendor\Module\Controller\Index;

use Magento\Framework\Controller\ResultFactory;
use Magento\Framework\App\Action\Context;
use Vendor\Module\Model\YourModel;
class Blog extends \Magento\Framework\App\Action\Action
{
    protected $model;
    protected $date;
    protected $customermodel;

    public function __construct(
        Context $context,
        YourModel $model,
        \Magento\Framework\Stdlib\DateTime\DateTime $date
    )
    {
        $this->model = $model;
        $this->date = $date;
        parent::__construct($context);
    }

    public function execute()
    {
        $query['question'] = $this->getRequest()->getPostValue("question");
        $query['email'] = $this->getRequest()->getPostValue("email");
        $query['product_name']=$this->getRequest()->getPostValue("product_name");
        $query['cutomer_name']=$this->getRequest()->getPostValue("customer_name");

        if ($query){

        $this->model->setData($query);
        $this->model->Save();
        $redirect = $this->resultFactory->create(ResultFactory::TYPE_REDIRECT);
        $redirect->setUrl($this->_redirect->getRefererUrl());
        $this->messageManager->addSuccess(__('You submitted your Question successfully.'));
        return $redirect;
        }
        else{
            $redirect = $this->resultFactory->create(ResultFactory::TYPE_REDIRECT);
            $redirect->setUrl($this->_redirect->getRefererUrl());
            $this->messageManager->addError (__('Failed To Submit  Please Provide Valid Data.'));
            return $redirect;
        }
    }
}

How to create custom forms in Magento 2:

• Step 1: Enable Custom Form module and go to Manage Forms field
• Step 2: Create a new custom form
• Step 3: Preview form in the frontend

That's it.

You must create a controller and then paste the below code in it and do not forgot to change the vendor and mdoulename with your own module name. There should be a model file as well.

namespace Vendor\modulename\Controller\Index;
use Magento\Framework\App\Action\Context;
use Magento\Framework\View\Result\PageFactory;
use vendor\modulename\Model\ExtensionFactory;
use Magento\Framework\Controller\ResultFactory;
use Magento\Framework\App\Action\Action;

class Submit extends Action
{
    protected $resultPageFactory;
    protected $extensionFactory;
    public function __construct(
        Context $context,
        PageFactory $resultPageFactory,
        ExtensionFactory $extensionFactory
    )
    {
        $this->resultPageFactory = $resultPageFactory;
        $this->extensionFactory = $extensionFactory;
        parent::__construct($context);
    }

    public function execute()
    {
        try {
            $data = (array)$this->getRequest()->getPost();
            if ($data) {
                $model = $this->extensionFactory->create();
                $model->setData($data)->save();
                $this->messageManager->addSuccessMessage(__("Data Saved Successfully."));
            }
        } catch (\Exception $e) {
            $this->messageManager->addErrorMessage($e, __("We can\'t submit your request, Please try again."));
        }
        $resultRedirect = $this->resultFactory->create(ResultFactory::TYPE_REDIRECT);
        $resultRedirect->setUrl($this->_redirect->getRefererUrl());
        return $resultRedirect;

    }
}