Padlock not shown

I was brought to my attention from my clients that my site wasn’t Https secure. I did a little research and was able to purchase a SSL certificate for my website. I then installed WordPress Https plugin. After I installed the plugin I noticed when I visit my site there is no Https padlock shown. I then called Godaddy for assistant, and apparently there are items in my site such as images or not secure. Godaddy advised me to ask my web designer guy to help me change the coding for those items. Unfortunately, my web guy had a falling out and we no longer are in contact with each other. Can anyone on here assist me on how to go about making these changes so that my site is fully secure? Thank you!