Recently had a brain mri shown couple of periventricular & subcortical white matters t2/flair what does it mean? does it indicate ms based on my symptoms? is it necessary to have spinal tap test? thanks?

It could represent multiple sclerosis, however, much less likely at age 56. It could be more concerning for mini strokes caused by undiagnosed atrial fibrillation. I would strongly recommend an evaluation by your PCP and neurology to further sort this out and put you on the proper prevention strategy.

Presumably you didn't just wander into an MRI facility & make an impulse purchase. A doctor ordered the test, & for a reason. What was the reason? The MRI isn't the patient; you are. Without the reason, the test is meaningless. The orderer of the test is ethically obligated to interpret its significance to you; or, if they can't, to find someone who can. You have a right to that. Be persistent.

In absence of any knowledge of your symptoms, prior history, and exam findings, it is literally impossible to correlate your MRI data which may or may not be nonspecific. Have a thorough conference with your doctor about the next appropriate steps.