The Rambam in הלכות יסודי התורה explains the Mitzva not to erase or destroy one of Hashem's holy names. There are primarily seven names that are forbidden to destroy. They are: the two ways of spelling Ado-nai, א-ל אלוקים אלוקינו ש-די and צב-אות. For erasing these names, one gets lashes. We are also not allowed to erase suffixes but prefixes such as the ב in בא-לוקים is not forbidden. If one tattooed one of these holy names, it is highly problematic as it cannot be defiled or disgraced. One should cover the name when he bathes or goes to an unclean place. If a Torah was written by an אפיקורס, a heretic, or an idol worshipper, or missionary, even though it contains one of these seven names, it should be burned. It has no sanctity and is highly טמא, impure.