This is based upon my personal experience so take this with a grain of salt as it’s not necessarily reflective of the entire industry…
Depending upon the company you work for they will either have a standard project lifecycle or you will need to create one. For example in my company we have a standard model that outlines 5 phases of a software development project from initiation through post deployment closeout. Within each phase are a set of activities and corresponding documentation that drive the project.
The responsibility of the PM is to work with the various groups (system architects, requirements analysts, developers, testers, etc.) to develop a timeline to meet all of those activities and a budget to track the effort and then ensure that the team meets those goals. If the project appears to be off track in either the timeline or the budget the PM works with the team to develop a mitigation plan to set it straight. This includes raising jeopardys to leadership so corrective action can be taken. Unfortunately this sometimes makes you the “bad guy”. For example I may need to go to my leadership and say “application team XXX is behind. They have 500 hours of work to do by the end of the month and the only way they will make it is for the entire crew to work weekends. The other option is to tell the customer we will be delivering 2 weeks late.”
Along the way there are multiple documents that are developed, reviewed and signed off on by the team. This ensures you are delivering a quality product and that all the teams are aware, and agree to their responsibility to deliver. The PM manages (but does not necessarily produce) this documentation.
People skills are vital as you will often be competing for resources with other projects and asking people to work through difficult issues. For example, if a requirement is misunderstood or poorly documented it may not be evident until coding. At this point the developers may want to say “not my issue” and the requirements team may say “the team signed off on it, we’ve moved on to another project” but you, the PM, need to get these groups to get back together to develop a solution and still try to meet you timeline and budget. Sometimes that’s possible, sometimes it’s not. When it’s not you will be required to explain to leadership what went wrong, so if you’re timid about difficult discussions with the senior leadership of your company you’ll need to get over that pretty quickly.
You may also be the primary contact with the client. At times you will need detailed information from them. They may not be responsive to your requests and you need to tactfully explain that failure to meet their responsibilities will affect the timeline and budget and that your company cannot be held responsible for those overruns if it is the result of a client issue. As you can imagine this is where you need to be firm yet tactful, it’s a tricky path to walk.
It can be rewarding and it’s a very visible position but it also carries a good deal of stress.
Lots of good info here: