Open https://www.openstreetmap.org/, look for the metro, right-click and ask for the object. Copy the name and go to https://overpass-turbo.eu/#.
(way["name"="ঢাকা মেট্রো লাইন ৬"](23.6685719, 90.273379,24, 90.5756343);>;);
out skel;
(node["name"="Uttara North"](23.6685719, 90.273379,24, 90.5756343);>;);
out skel;
(node["name"="Uttara Center"](23.6685719, 90.273379,24, 90.5756343);>;);
out skel;
(node["name"="Uttara South"](23.6685719, 90.273379,24, 90.5756343);>;);
out skel;
(node["name"="Pallabi"](23.6685719, 90.273379,24, 90.5756343);>;);
out skel;
(node["name"="Mirpur 11"](23.6685719, 90.273379,24, 90.5756343);>;);
out skel;
(node["name"="Mirpur-10"](23.6685719, 90.273379,24, 90.5756343);>;);
out skel;
(node["name"="Kazipara"](23.6685719, 90.273379,24, 90.5756343);>;);
out skel;
(node["name"="Shewrapara"](23.6685719, 90.273379,24, 90.5756343);>;);
out skel;
(node["name"="Agargaon"](23.6685719, 90.273379,24, 90.5756343);>;);
out skel;
(node["name"="Bijoy Sarani"](23.6685719, 90.273379,24, 90.5756343);>;);
out skel;
(node["name"="Farmgate"](23.6685719, 90.273379,24, 90.5756343);>;);
out skel;
(node["name"="Karwan Bazar"](23.6685719, 90.273379,24, 90.5756343);>;);
out skel;
(node["name"="Shahbag"](23.6685719, 90.273379,24, 90.5756343);>;);
out skel;
(node["name"="Dhaka University"](23.6685719, 90.273379,24, 90.5756343);>;);
out skel;
(node["name"="Bangladesh Secretariat"](23.6685719, 90.273379,24, 90.5756343);>;);
out skel;
(node["name"="Motijheel"](23.6685719, 90.273379,24, 90.5756343);>;);
out skel;
Click on Export as GeoJSON and import that at http://geojson.io/.
Or import at https://mapshaper.org/ and export as SVG.