To deal with leash anxiety, get some high value treats and only get them out when the lead is in sight and only give the treat when the collar/lead/harness is in view. When the lead goes out of sight, so does the reward. They need to make a positive association that when the lead comes out, good things happen. Don't attempt to put the collar/harness/lead on straight away, just gradually move it closer and reward each positive interaction with it. Touch the lead against the body and reward, but still don't attempt to clip it on. Clip on but don't hold onto the end, reward. Reward each time you touch the lead, but don't restrain or hold onto the lead. Unclip the lead and reward. Repeat until there is no fear of the lead being clipped on.
Try not to lean over a dog to put their harness on as this is very intimidating for a dog and will make their heart rate rise. Create a positive association, gradually build up with lots of positive rewards, reward every interaction. When working on the lead anxiety, first get used to wearing a harness, then attach a 5 meter line but don’t hold it, practice walking up and down in the garden with lots of treats. Walking up and down the garden with all 5 meters keeping it nice and loose, lots of praise and reward, then gradually shorten the lead but keep it nice and loose. Gradually start to walk to other places with lots of praise, keeping lead nice and slack, be happy to turn around or change direction if necessary, but don't drag her if she wont come and try not to let her pull. Attach lead but don't hold it, leave the lead trailing to build confidence and reward with lots of treats. Shorten the lead gradually as anxiety improves, keep it nice and slack and be prepared to let go if necessary.