Fixation of the header posts area in blogger's template is an another crucial task to actualize the margin distribution needs in hearder post area to manage the looks of adds and some vital steps can solve the hitch.
Step 1 Login to Blogger > Go To Dashboard > Edit Html > Expand Widgets
Step 2 Find the following code > (Click Ctrl and F for a search bar)
]]></b:skin>
Step 3 Place blow mention codes before step 2 mention code and press enter.
.post-header {
.post-header {
margin: 0 0 0em;
}
}
Margin can be increased or decreased as per requirement. afterwards you can preview the template if every things are OK then save the template.

