Every person arrested and subjected to questioning must first be informed of their Miranda rights. The Miranda rule was created by the Supreme Court many years ago to protect and enforce your Constitutionally based 5th Amendment right against self incrimination when charged with a crime. Those rights include the right to remain silent, the right to have an attorney present during questioning and the warning that anything that is said will be used against you.
Of course, Investigating police officers always want the person they have arrested to make a statement. That is because most of the statements made by people accused of crimes are either outright confessions which make prosecuting the case much easier or at the very least admissions of facts which will help the prosecutor prove the case.
Most Detectives and many uniformed officers are trained to use interrogation tactics to obtain a statement. Some of the tactics are very subtle and seem benign and others are quite aggressive. These tactics might include misstatements and outright lies about the nature and existence of the evidence available against you, question first tactics (recently ruled unconstitutional by the Supreme Court in Missouri v. Seibert, but still prevalent ) indirect questioning (the “functional equivalent” of direct questioning as described in Rhode Island v. Innis, also unconstitutional but still common), promises to help with your case or other inducements (often illegal under Maryland Common Law) and many other techniques.
Every case is different and no blanket advice can be given about whether you should make a statement before or after you are arrested. Consultation with an attorney before making a statement is crucial. Any statement which could be made without an attorney can still be made with an attorney and after you have full knowledge of your rights.