Q.should we peel off loose bark?
Large pieces are peeling. Can we spray it? I once saw a can of spray (it was like tar). Is that helpful?

What kind of tree is this? The reason I ask is that peeling bark on some trees is a completely normal process. However, it could also be a sign of pests or disease (do you see anything unusual on the tree - insects, holes, funguses, etc?) I recommend that we make a determination on why this is happening before peeling off bark or spraying it. Because, if there's an underlying issue, the underlying issue needs to be remedied first. Here is an article on peeling tree bark that will help you:
https://www.gardeningknowhow.com/ornamental/trees/tgen/peeling-bark-on-trees.htm