Atypical ecg? Is says sinus rhythm and low qrs voltage in chest leads (qrs deflection <1.0 mv in chest leads) what does that mean?

Maybe normal. May be normal variant. An old ECG would be helpful. Other things such as pericardial effusion or water around the heart may be a cause. If you have no symptoms and it's not a change from old ECG then prob not an issue.
Overweight? Probably nothing important. Low qrs waves are seen in obese or hypothyroid ( large or big patients )pts or hyperinflated pts ( COPD or emphysema). But may be a technical error.
Mostly nothing bad. In most cases it does not mean anything bad. Low voltage can be typically seen in women because of the breast tissue between the heart and the electrodes, persons of small build because there heart is smaller, people with thick chest wall with lot of muscle, bone and or muscle between the heart and the electrodes and also in persons with lung disease such as emphysema because of all the air.