This method utilizes Google Sheets (within your Google account). This method involves using the script editor within Sheets. This will populate the fields with latitude and longitude.
This is one of my favorite methods. This one again uses the Google Sheets script editor. You will need to copy/paste the code from the link.
Mapcite is a downloadable addin for Excel. There are paid and free versions. The free version only allows you to geocode up to 100 lines. I've found the licensing for the free version to be a bit confusing. But it is a great product.
Like most esri stuff, it works great but costs money. You need an account and will consume credits (that you pay for) to geocode.
This is another online option (no downloads or installs). You need to obtain the keys needed to get any use out of this site.
This is another online option (no downloads or installs). One copies and pastes their data. There appaers to be no limits, registration, or costs. Probably my favorite online geocode option.
Another one I did not personally try. Need to register. You can add addresses directly from Google Sheets and dowload a kml.
The key with this is to download the newly free Google Earth Pro. Again, this will map your points but not give you latitude and longitude. With Google Earth, you can convert your points to kml. Than you can calculate the lat/long using the kml and ArcMap (calculate geometry) or QGIS (field calculator).
This method utilizes LibreOffice Calc (or OpenOffice). This method was a little less straightforward than the other methods I looked at. But it definitely worked.
This method assumes you have downloaded/installed QGIS. This methods worked extremely well. First, your data must be in a .CSV format. You will also need to add the MMQGIS plugin. This method will generate a shapefile but not populate fields with latitude and longitude. But a quick use of the Field Calculator will generate the lat/long for you.
This website is nice because it is online. There is no need to download or install anything. It can do single or batch geocoding.
This is an online option (no downloads or installs). You are required to give an email address. It generates a map showing your points but it does give you the option to download the points as a kml file (which you could convert later).
This is an Excel addin. You need to have an organizational (paid) account to use it and you consume credits when you geocode with it.
One has to register and there are free and paid versions. Free has 7500 geocodes/month. I did not personally try this site.
This is an Excel addin crated by Microsoft. It works for Office 2013 or Office 365. You can insert a Bing map or Power Map.