If you only want to obtain higher daily quota (10,000 calls per days instead of 300) you supply the `key` value as query parameter on the url. The `key` value is found in your App management page. See [I only need a key, what do I do?](https://stackapps.com/a/8972)

If you also want to supply an `access_token` you can obtain one relative quickly by using below script.

1. In your App management page, configure your app for Client Side OAuth Flow:<br><br>
[![enter image description here][1]][1] <br>
And submit that setting.

2. Copy and/or remember the Client Id from your App management page. (that is the first value near the top of the page)

3. Run below script and paste / type the client id in the client id field and select a scope. You can select 'no_expiry' as initial/only option.

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-js -->

    (function(window, document) {
      var redirectUri = 'https://stackexchange.com/oauth/login_success',
          scope = {},
          clientid;
     
      function buildScope() {
        var selectedScope = []
        for(const key in scope) {
          if (scope[key] === true) {
            selectedScope.push(key);
          }
        }
        return selectedScope;
      }
      
      function updateUrl() {
        var authurl = document.getElementById('authurl');
        authurl.value = 'https://stackoverflow.com/oauth/dialog' +
          '?' +
          'client_id=' + clientid +
          '&' + 
          'scope=' + buildScope() +
          '&' +
          'redirect_uri=' + redirectUri;
      }

      function updateScope(evt) {
        scope[evt.target.value] = evt.target.checked;
        updateUrl();
      }
      
      function updateClientId(evt) {
         if (clientid = evt.target.value) {
            updateUrl();
         }
      }

      function start() {
        var client_id = document.getElementById('client-id');
        client_id.addEventListener('change', updateClientId);
        client_id.addEventListener('keydown', updateClientId);
        
        document.querySelectorAll('input[type="checkbox"]').forEach(function(checkbox) {
           checkbox.addEventListener('change', updateScope);
        })
      }
      
      window.addEventListener('load', start);

    })(window, document)

<!-- language: lang-css -->

    textarea { width: 100%}

<!-- language: lang-html -->

    <fieldset>
      <label for='client-id'>Client Id</label>
      <input id='client-id' type='text' />
    </fieldset>

    <fieldset>
    <h2>Scope (tick at least one)</h2>
    <div>
    <input id='no_expiry' type='checkbox' value='no_expiry'/>
    <label for='no_expiry'>access_token's with this scope do not expire</label>
    </div>
    <div>
    <input id='read_inbox' type='checkbox' value='read_inbox'/>
    <label for='read_inbox'>access a user's global inbox</label>
    </div>
    <div>
    <input id='write_access' type='checkbox' value='write_access'/>
    <label for='write_access'>perform write operations as a user </label>
    </div>
    <div>
    <input id='private_info' type='checkbox' value='private_info'/>
    <label for='private_info'>access full history of a user's private actions on the site</label>
    </div>

    </fieldset>
    <div>
    <h2>Copy below url and paste in a new browser tab</h2>
    <textarea id='authurl' readonly='readonly'></textarea>
    <p>
    Once authenticated you'll find your token at the end of the https://stackexchange.com/oauth/login_success Url.
    </p>
    </div>

<!-- end snippet -->

4. Copy the resulting URL from the large text area, open a new browser tab/window and paste the URL. You're now shown the name and description of your App and you can accept/allow the app access. 

5. You're redirected to the login_success page. Its URL has your access_token appended after the `#` symbol in the url. <br><br>
[![enter image description here][2]][2] <br>
That is the access_token for you to keep. Careful! That token is a secret. Don't share it, ever.


  [1]: https://i.sstatic.net/qmAmd.png
  [2]: https://i.sstatic.net/dkzyA.png