If you need to use a workflow it can be done using SharePoint designer workflows.
I am guessing you do not have SharePoint designer.
It is a free tool provided by microsoft, so please download it for the version of SharePoint you have (SharePoint designer for 2013/2010/2007)
- If you do have it, or once you download it, run your SharePoint designer.
- Once you start it you will need to open your SharePoint site, which contains the list you need that workflow for. So click Open Site and enter the URL.
- Either navigate to the list and click "List Workflow" in the ribbon, or click "List Workflow" from Home and select the list you need.
- Enter name and description for workflow and you will be taken to workflow content editor.
- Click "Condition" in the ribbon.
You will define what conditions need to be met for the workflow to send emails. If you want your WF to always send once a new item is created, simply select "If current item field equals value", select "Requesting team" as the field, click operator (by default it is set to "equals") and select "is not empty"
- Now click "Action" in the ribbon.
- Select "Send email".
- Click "These users" to modify the users.
- Click the book icon next to "To:" field.
- Select "Workflow Lookup for a User".
- Leave "Current Item" as data source.
- Set "Requesting team" as Field from source.
- Set "Email Address" to Return the field data email address.
- Define email content, you can use data from your SharePoint to customize the messages.
- Set the workflow triggers.
To do that, click "Workflow settings" in the ribbon and select "Start workflow automatically when an item is created" under Start Options.
- Save and publish the workflow. You can do that by clicking corresponding buttons in the ribon.
Your workflow should be ready. Make sure that group members have correctly defined emails and you web application SMTP settings are correct for outgoing emails.
That is out of the box way.
You can also use third party solutions for an easier management. For example i believe you could use an alerting tool to send these emails. There are a lot of those, i would recommend JungleBell as it is probably the easiest to use: